CVE-2025-21121 Overview
CVE-2025-21121 is an out-of-bounds write vulnerability [CWE-787] affecting Adobe InDesign Desktop. The flaw exists in versions ID20.0, ID19.5.1, and earlier on both Windows and macOS platforms. Attackers can achieve arbitrary code execution in the context of the current user by convincing a victim to open a maliciously crafted file. Adobe disclosed the issue in security bulletin APSB25-01 on February 11, 2025. Exploitation requires user interaction, but no authentication is needed, and the attack complexity is low.
Critical Impact
Successful exploitation grants arbitrary code execution under the privileges of the user running InDesign, enabling malware installation, data theft, and lateral movement.
Affected Products
- Adobe InDesign Desktop ID20.0
- Adobe InDesign Desktop ID19.5.1 and earlier
- Microsoft Windows and Apple macOS installations of the affected versions
Discovery Timeline
- 2025-02-11 - Adobe publishes security advisory APSB25-01
- 2025-02-11 - CVE-2025-21121 published to NVD
- 2025-03-03 - Last updated in NVD database
Technical Details for CVE-2025-21121
Vulnerability Analysis
The vulnerability is an out-of-bounds write condition within the InDesign Desktop application. When InDesign parses a malformed document, the application writes data past the boundary of an allocated buffer. This memory corruption can overwrite adjacent structures, including function pointers or heap metadata, leading to arbitrary code execution.
The issue is classified under [CWE-787], which covers improper bounds checking during memory write operations. Because InDesign processes complex document formats with embedded objects, fonts, and image data, parsing routines provide a broad attack surface for crafted input.
Execution occurs in the context of the user opening the file. On most desktop deployments, this grants the attacker the same access rights as the victim, including access to documents, credentials cached in the user profile, and connected network resources.
Root Cause
The root cause is insufficient validation of size or index values when writing data to a memory buffer during file parsing. The application trusts attacker-controlled fields in the document structure, allowing a write beyond the intended allocation. Adobe has not published the specific component or parsing routine responsible.
Attack Vector
The attack vector is local and requires user interaction. An attacker delivers a crafted InDesign file through email, web download, file share, or removable media. When the victim opens the file in a vulnerable version of InDesign, the parser triggers the out-of-bounds write and executes attacker-supplied code. No network exposure of the application is required.
No public proof-of-concept exploit code is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
Detection Methods for CVE-2025-21121
Indicators of Compromise
- Unexpected child processes spawned by InDesign.exe on Windows or the Adobe InDesign process on macOS, particularly shells, scripting hosts, or rundll32.exe.
- InDesign process crashes or Windows Error Reporting events referencing memory access violations shortly after opening a document.
- InDesign document files (.indd, .indt, .idml) originating from untrusted email attachments or external file shares.
- Outbound network connections initiated by the InDesign process to unfamiliar hosts.
Detection Strategies
- Monitor process creation telemetry for InDesign spawning interpreters such as powershell.exe, cmd.exe, wscript.exe, or osascript.
- Apply behavioral identification rules that flag memory corruption patterns and shellcode execution within document handling applications.
- Inspect email gateways and web proxies for inbound InDesign document files and quarantine those from unverified senders.
Monitoring Recommendations
- Track InDesign version inventory across endpoints to identify systems still running ID20.0 or ID19.5.1 and earlier.
- Collect endpoint EDR telemetry covering process trees, file writes, and network connections originating from Adobe applications.
- Correlate crash reports referencing InDesign modules with file open events to surface attempted exploitation.
How to Mitigate CVE-2025-21121
Immediate Actions Required
- Update Adobe InDesign to the fixed versions listed in Adobe security bulletin APSB25-01 on every affected workstation.
- Block inbound InDesign document files at email and web gateways until patching is verified across the environment.
- Instruct users to avoid opening .indd, .indt, or .idml files received from untrusted sources.
Patch Information
Adobe released fixed versions of InDesign Desktop addressing this vulnerability. Refer to the Adobe Security Advisory APSB25-01 for specific patched version numbers and download locations for Windows and macOS.
Workarounds
- Restrict InDesign usage to non-privileged user accounts to limit the impact of successful exploitation.
- Enable application allowlisting to prevent child processes such as command interpreters from launching from InDesign.
- Use sandboxing or virtual desktop infrastructure to isolate document handling from sensitive corporate resources.
- Disable file association handlers that auto-open InDesign documents from email clients or browsers.
# Verify installed InDesign version on macOS
defaults read "/Applications/Adobe InDesign 2025/Adobe InDesign 2025.app/Contents/Info.plist" CFBundleShortVersionString
# Verify installed InDesign version on Windows (PowerShell)
Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*" |
Where-Object { $_.DisplayName -like "*InDesign*" } |
Select-Object DisplayName, DisplayVersion
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
